Solubility of a New Cardioactive Prototype Drug in Ionic Liquids

Solubility in different solvents is an intrinsic material characteristic for a defined molecule. The solubility of a new cardioactive prototype drug, 3,4-methylenedioxybenzoyl-2-thienylhydrazone (LASSBio-294), was determined in seven different imidazolium based ionic liquids (ILs). The ionic liquids selected were 1-ethyl-3-methylimidazolium methyl phosphonate; 1-ethyl-3-methylimidazolium ethyl phosphonate; 1-ethyl-3-methylimidazolium acetate; 1,3-dimethylimidazolium methyl phosphonate; 1-butyl-3-methylimidazoilium acetate; 1-butyl-3-methylimidazolium tetrafluoroborate; and 1-butyl-3-methylimidazolium bis(trifluoromethane-sulfonyl)imide. In addition, solubility data of LASSBio-294 in water and in mixtures of water and ILs were also measured. For all solvents, the concentration of drug in saturated solutions was determined by high performance liquid chromatography (HPLC). Solid liquid equilibrium measurements were performed in a range of temperatures from 288.15 K to 308.15 K, at atmospheric pressure. From the solubility data it can be concluded that the drug showed sufficient solubility in five of the tested ILs so that these compounds can be suitable for further crystallization studies. The aim of this work is also to discuss and understand the solubility of LASSBio-294 in these alternative solvents. The results indicate that the solubility of the drug is dependent on IL structural variations (cation anion combinations).